A frequency divider or a clock divider is a circuit that receives an input signal having a frequency fin and generates an output signal of a frequency:fout=fin/n, where n is an integer. A divider-based counter uses a frequency divider circuit and logic circuitry to generate a count from the edges of an input clock. Divider-based counters can be used in Voltage-Controlled Oscillator (VCO)/Current-Controlled Oscillator (CCO)-based quantizers. For low power operation, divider-based counters (e.g., asynchronous or ripple counters) provide power savings due to frequency division of each divider stage. In VCO/CCO-based quantizers, an input signal modulates the frequency of a ring oscillator, the phases of the ring oscillator may be sampled at certain time instances and the phase increment between consecutive samples determined. For every period of an N-stage ring oscillator where N is an odd integer greater than or equal to three, sampled ring outputs (e.g., N-bit outputs) may be decoded to 1 of 2N discrete states. Thus, a quantizer is obtained and provided with the 1 to 2N discrete states.
The least significant bits (LSB) of the quantizer obtained by sampling the ring oscillator's N outputs is 2π/2N. In applications where the sampling of the phase is much slower than the frequency of oscillation, the phase may wrap around multiple times, creating ambiguity in the phase measurements. For example, if the phase is decoded to k*2π/2N, then it is possible that the phase increment between consecutive samples of the outputs of the ring oscillators was one of:
      k    ⁢                  2        ⁢        π                    2        ⁢        N              ,          ⁢            (              k        +                  2          ⁢          N                    )        ⁢                  2        ⁢        π                    2        ⁢        N              ,          ⁢            (              k        +                  4          ⁢          N                    )        ⁢                  2        ⁢        π                    2        ⁢        N              ,          ⁢            (              k        +                  6          ⁢          N                    )        ⁢                  2        ⁢        π                    2        ⁢        N              ,or the like. Thus, improved dividers and counters that increase the number of states in the counter to remove the ambiguity are needed or desired.
Shortcomings mentioned here are only representative and are included simply to highlight that a need exists for improved electrical components, particularly for dividers, and electrical parts that include dividers, employed in consumer-level devices, such as mobile phones. Embodiments described herein address certain shortcomings but not necessarily each and every one described here or known in the art.